LetExp([
 FunctionDec[
  (printint,[
   (i,false,int)],
   NONE,
   LetExp([
    FunctionDec[
     (f,[
      (i,false,int)],
      NONE,
      IfExp(
       OpExp(GtOp,
        VarExp(
         SimpleVar(i)),
        IntExp(0)),
       SeqExp[
        CallExp(f,[
         OpExp(DivideOp,
          VarExp(
           SimpleVar(i)),
          IntExp(10))]),
        CallExp(print,[
         CallExp(chr,[
          OpExp(PlusOp,
           OpExp(MinusOp,
            VarExp(
             SimpleVar(i)),
            OpExp(TimesOp,
             OpExp(DivideOp,
              VarExp(
               SimpleVar(i)),
              IntExp(10)),
             IntExp(10))),
           CallExp(ord,[
            StringExp("0")]))])])]))]],
    IfExp(
     OpExp(LtOp,
      VarExp(
       SimpleVar(i)),
      IntExp(0)),
     SeqExp[
      CallExp(print,[
       StringExp("-")]),
      CallExp(f,[
       OpExp(MinusOp,
        IntExp(0),
        VarExp(
         SimpleVar(i)))])],
     IfExp(
      OpExp(GtOp,
       VarExp(
        SimpleVar(i)),
       IntExp(0)),
      CallExp(f,[
       VarExp(
        SimpleVar(i))]),
      CallExp(print,[
       StringExp("0")]))))),
  (nfactor,[
   (n,false,int)],
   SOME(int),
   IfExp(
    OpExp(EqOp,
     VarExp(
      SimpleVar(n)),
     IntExp(0)),
    IntExp(1),
    OpExp(TimesOp,
     VarExp(
      SimpleVar(n)),
     CallExp(nfactor,[
      OpExp(MinusOp,
       VarExp(
        SimpleVar(n)),
       IntExp(1))]))))]],
 SeqExp[
  CallExp(printint,[
   CallExp(nfactor,[
    IntExp(6)])]),
  CallExp(print,[
   StringExp("
")])])